Definition: You are given a question on high school biology. You are also given 4 answer options (associated with "A", "B", "C", "D"), out of which only one is correct. You need to answer the question by selecting the correct option. You should only answer with the choice letter, not the whole answer.
Input: Which of the following theories is based on the notion that mitochondria and chloroplasts evolved from prokaryotic cells?
(A)Fluid mosaic model (B)Endosymbiotic model (C)Taxonomic model (D)Respiration feedback model

B